<div ng-controller="DebugController">
  <span ng-click="visible = !visible" class="normal-action">
    <i class="fa fa-fw fa-chevron-circle-{{visible ? 'up' : 'down'}}"></i> {{visible ? 'hide' : 'show'}} log
  </span>
  <div ng-repeat="msg in messages track by $index">
    {{msg}}
  </div>
</div>